The Journal of the Korea Contents Association (한국콘텐츠학회논문지)

The Korea Contents Association (한국콘텐츠학회)
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Evaluation of the dose of 16-MDCT and 64-MDCT in case of Coronary Artery CT Angiography using Thermoluminescence Dosimeter

열형광선량계를 이용한 16-MDCT와 64-MDCT의 관상동맥 CT 혈관조영술 시 선량평가

  • 김상태 (전북대학교 방사선과학기술학과, 분당서울대학교병원 영상의학과) ;
  • 최지원 (전주대학교 방사선학과) ;
  • 조정근 (전주대학교 방사선학과)
  • Received : 2010.02.09
  • Accepted : 2010.05.03
  • Published : 2010.06.28
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Abstract

Coronary artery CT angiography has short scanning length, the exposure dose is high. Therefore, it is required to study on the organ dose when using MDCT. We compared the differences between the absorbed dose and effective dose in the major organs assessing the absorbed dose in the major organs by 16-MDCT and 64-MDCT in the subjects with coronary artery CT angiography, the same protocol by 16-MDCT and 64-MDCT. As a result, the great orders of absorbed dose when conducting coronary artery CT angiography had been shown as heart, stomach, liver, pancreas, kidney, spleen, large intestine, lung, small intestine, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.538{\pm}0.026(Mean{\pm}SD,\;p<0.05)mGy{\sim}71.316{\pm}4.316mGy$ in 16-MDCT, and heart, stomach, pancreas, spleen, liver, kidney, small intestine, large intestine, lung, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.87{\pm}0.01mGy{\sim}115.26{\pm}1.59mGy$ in 64-MDCT, demonstrating some different distributions. The exposed doses to the patient per one time scanning with coronary artery CT angiography were $71.316{\pm}4.316mGy$ in 16-MDCT as the absorbed dose based on the heart and $115.26{\pm}1.59mGy$ in 64-MDCT. The effective doses were 7.41 mSv and 12.11 mSv in 16 and 64-MDCT, respectively. Taking into account the results of brain CT with 2.8 mSv that has comparatively large scanning length and size, facial CT 0.8 mSv, chest CT 5.7 mSv, pelvic CT 7.2 mSv, and abdominal and pelvic CT 14.4 mSv, it is very high considering the scanning length of 13 cm limited to the heart for the scanning range.

관상동맥 CT 혈관조영술(coronary artery CT angiography)은 작은 스캔 길이에도 불구하고 방사선량이 높다. 3차원 영상을 얻기 위해서 다른 방사선 검사보다 고 선량(high dose)이 조사되는 CT촬영으로 인한 방사선 피폭이 중요한 문제로 대두되고 있어 MDCT의 이용 시 장기선량에 대한 고찰이 필요하다. 16-MDCT와 64-MDCT에서 동일 프로토콜의 관상동맥 CT 혈관조영술을 대상으로 16-MDCT와 64-MDCT에서의 주요장기의 흡수선량을 측정하여 주선속 내외의 주요장기 흡수선량 및 유효선량의 차이를 비교하였다. 그 결과 관상동맥 CT 혈관조영술시 받는 흡수선량이 큰 조직 순으로 열거하면 16-MDCT에서 심장, 위, 간, 췌장, 신장, 비장, 대장, 폐, 소장, 갑상선, 난소, 방광, 안와 순으로 $0.538{\pm}0.026(Mean{\pm}SD,\;p<0.05)mGy{\sim}71.316{\pm}4.316mGy$의 흡수선량 분포를 나타냈으며 64-MDCT에서는 심장, 위, 췌장, 비장, 간, 신장, 소장, 대장, 폐, 갑상선, 난소, 방광, 안와 순으로 $0.87{\pm}0.01mGy{\sim}115.26{\pm}1.59mGy$의 흡수선량 분포를 나타내 16-MDCT와는 그 분포 형태가 다소 다르게 나타났다. 관상동맥 CT 혈관조영술 1회 촬영으로 받는 환자선량이 16-MDCT에서 심장을 기준으로 한 흡수선량이 $71.316{\pm}4.316mGy$였으며 64-MDCT에서는 $115.26{\pm}1.59mGy$로 나타났고 유효선량은 16-MDCT에서 7.41 mSv, 64-MDCT에서 12.11 mSv로 나타났다. 상대적으로 스캔길이와 면적이 비교적 큰 뇌 CT 2.8 mSv, 안면-도관 CT 0.8 mSv, 가슴 CT 5.7 mSv, 골반 CT 7.2 mSv, 복부와 골반 CT에서 14.4 mSv임을 감안할 때 스캔구간이 심장에 제한된 13 cm의 스캔길이를 고려하면 상당히 높다. 그러나 주어진 진료 목적을 달성하면서 환자의 선량을 감축할 수 있다면 그러한 노력을 게을리 하지 말아야 할 것이다.

Keywords

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